Hi, I'm currently using Traveler's Backpack on Forge, version 1.20.1. I'm using the Aternos free-to-use servers as a way to play with friends without putting too much effort into making a server that will get used maybe two months out of the year.

We noticed this issue early on since we have used this mod on multiple other versions (typically Fabric though). When someone places their backpack or goes up to a backpack and breaks it to pick it up, all the contents and upgrades are removed.

This is done either when placing the backpack you have items in/upgraded on the floor or die from a monster and have it placed on the floor. When you go to pick up the backpack, break it with your fist, pickaxe, axe, etc. the contents and upgrades are removed.

Previously, this wasn't the case. When you broke the backpack to pick it up (since sometimes you carry more than one for storage convenience), all contents and upgrades were still in the backpack.

I can take a video if that makes the problem easier to understand since it is a little hard to describe without sounding repetitive.

Update to latest alpha for 1.20.1, I fixed it